Polyolefin polymers compositions have gained wide acceptance and usage in numerous commercial applications because of the relatively low cost of the polymers and the desirable properties they exhibit. Such commercial applications include plastic film, such as cast and biaxially oriented films, for food packaging, containers for food and medical devices such as syringes. It is very important for materials used as containers for foods and medical devices that the presence or absence of impurities or foreign substances such as refuse or the like in the contents of a container can be externally confirmed and it is not desirable that the color tint of the contents be changed when it is observed through the container. For this reason, it is desired to use a polymer composition of good transparency or clarity, in these fields.
There has widely been used a method for improving the clarity or transparency of polymer composition, in particular polypropylene resins, which comprises incorporating a sorbitol derivative into the resins. Yokote et al, U.S. Pat. No. 5,153,249 discloses a polypropylene resin composition which incorporates an additive package of 1-3, 2-4 di-benzylidene sorbitol and talc which are well-known nucleating additives.
Although the reference cited above teaches a copolymer composition exhibiting some improvement in optical properties, it would be of advantage to provide improved random copolymer compositions including a process for producing the improved copolymer compositions, having an improved balance of low haze (i.e., good transparency), low hexane extractables content, and low heat seal initiation temperature.